A fine processing technology of a semiconductor device acceleratively progresses. In a semiconductor device, a fine pattern is formed by using a photolithography technique. However, as can be seen from the following equation (1), a diffraction limit exists in the resolution HP of photolithography in accordance with a wavelength. For this reason, the resolution HP of photolithography has a limit.HP=k1·λ/(NA)   (1)
where, λ is an exposure wavelength, k1 is a process factor (k1 factor: constant), and NA is a numerical aperture of a projection lens.
When photolithography is applied in order to form an nm-order fine pattern, there is a need to use shorter a wavelength such as ultraviolet rays or an X-ray. However, a light source is expensive, then the foregoing photolithography is not adaptable to mass production. Considering the foregoing circumstances, a relatively low-cost fine pattern forming method, which does not depend on the wavelength, such as near-field lithography or near-filed assist nano-imprint has been developed (e.g., see Jpn. Pat. Appln. KOKAI Publication No. 2006-287012).
According to the near-filed assist nano-imprint technique using metal disclosed in Publication No. 2006-287012, a pattern is formed by near-filed having amplitude distribution generated around the metal, but due to an error of light irradiation time or non-uniformity of light amplitude, a dimension error arises in the pattern. This results from the factor that the near-field amplitude distribution changes exponentially from the surface.